The price label system according to the present invention is generally an electronic pricing and information system that replaces the old paper labels with electronic labels where the process on labels can be wirelessly changed from a computer.
The actual price changes are not done in the price label system, but in the store's Price Controlling Application (PCA) system. The PCA contains a database which stores all the information about the items in the store, e.g. product name, package size, and the current price. The store's cash registers are connected to the PCA system, and thus always have the correct price information. The PCA can e.g. be the store's back-office computer system. There are no limitations regarding host computers for the PCA and the price label system server. They may be run on the same computer or in two (or more) different computers.
The PCA system controls the actual price of an item and provides the price label system according to the invention with updating information whenever the price is hanged. The PCA system interacts with the price label system to supply information to the price labels (PLs). This is normally performed via a Price File Interface (PFI) that is a software-to software interface connecting the PCA system to the price label system server. The only prerequisite is that all PFI files (see below) are reachable (can be read and written) within any path of a mounted drive or file system known to the computer where the PFI service is executing. The transportation mechanisms through the PFI are e.g. common text files, e.g. in 8-bit ASCII format or 2-byte UNICODE. Other transportation mechanisms are naturally possible. The price label system automatically detects the format of the input files. Two PFI files are created by the PCA, a message file and a data file.
The price label system creates a third PFI file, a result file that is retrieved by the PCA.
The message file contains one or my commands to the price label, e.g. a target link command used to establish the connection between an item and a label and an update command used to change the information an the label, e.g. the price. The data file contains data such as prices, item identity and label identity and the result file contains the results from executed commands.
The price label system generally comprises software installed in a server computer, a hardware infrastructure and price labels. The hardware infrastructure comprises base stations, transceivers and cables. The price labels are mounted with their items in the store, e.g. on the shelf-edges. Transceivers are normally mounted in the ceiling and base stations normally on a wall. A predetermined number of transceivers are connected to a base station, which is connected to the price label system server, preferably via a hub. The price label server is connected to the PCA, often via the same network.
FIG. 1 schematically illustrates an overview of the PCA and the price label system briefly described above and in accordance with well-established technique where the present invention is applicable.
When a price is changed in the PCA system, the information is sent to the price label system server (PLS server). From the PLS server, designated as “serve” in FIG. 1, the information is sent via a hub and base stations BS to transceivers in the ceiling where it is transformed into infrared signals. When the electronic price labels receive the infrared signals the price is immediately updated.
Each electronic price label acknowledges the updated price by transmitting a feedback pulse to the transceivers. The feedback pulse is returned to the server and stored in a database to verify that the transmission was OK.
Although the system shown in FIG. 1 uses infrared signals when communicating with the price label it should be noted that the present invention is equally applicable for any type of communication signal used between the price label system and the price labels.
Among different types of communication signal applicable in the system can be mentioned radio wave signals, optical signals, electrical signals.
A cell is defined as the set of transceivers connected to the same base station. A sub-cell is defined as each set of simultaneously transmitting transceivers. All transceivers within a sub-cell simultaneously transmit the same date. A power supply energizes the transmitting transceivers.
FIG. 2 illustrates an example of an installation plan with one cell comprising three sub-cells, SC1, SC2 and SC3, respectively. Each sub-cell includes a number of transceivers TRX. When configuring cells and sub-cells many different things must be considered. Among those can be mentioned that cables to transceivers within one sub-cell must be of sir lengths in order to minimize phase shifts and that sub-cells should overlap in order to ensure signals of sufficient strengths to all labels.
A benefit of the sub-cell concept is that it is possible to keep track of price label locations and that a label that does not respond can be paged (searched for).
A price label (PL) is an electronic device provided with an LCD display with the shape and size of a regular shelf-edge price label. Each PL has a unique address and is logically connected to a sales item in the store. Normally the PL displays an item's price. FIG. 3a shows a typical price label where all fields are active and FIG. 3b shows a price label displaying normal price and normal unit price. A sender and transmitter part 2 and a small solar cell 4 can also be seen on the price label in FIG. 3b. A battery, or a combination of battery and solar cell, provides the power for the PL.
There exists many different kinds of price labels, they can e.g. differ in size, in number of price fields or other fields. The word “price” is used throughout the application to define what is displayed on the price label. It should however be noted that although the price label often displays price information it is naturally possible to display other type of information on the price labels, solely or in addition to price information, without departing from the scope of the present invention. This other type of information may for example be text, figures or images.
The labels can also differ in the way the price label system needs to handle them, e.g. with regard to used communication protocol, and if the circuitry inside the price label has been changed.
The communication between the price label server and a price label is inter alia determined by the value of two parameters: price label family (PL family) and price label family revision (PL family revision).
The PL family is an administrative or logical entity that is used to group price labels together with similar communication features.
The PL family revision is used to denote minor differences in the values of the protocol parameters. A PL family may comprise several PL family revisions. To each physical price label is associated a PL type that encompasses the PL family and the PL family revision.
The communication protocol parameters are collected in protocol objects in the price label server. In a normally configured price label system typically includes a number of such protocol objects to be used when communicating with different kinds of price labels.
A protocol object comprises e.g. parameter settings regarding the number of re-transmissions, re-calibration time, and physical protocol identity.
When the server is about to communicate with a specific price label it needs to determine what protocol object to use.
According to a presently used system a specific price label type (with specific values of family and revision) is mapped to a specific protocol. FIG. 4 schematically illustrates this. In this case the communication between all physical price labels of the same PL type and the server is always performed in the same way, detained by the protocol objects settings.
However, in certain situations, e.g. due to environmental circumstances, if the price label is located in a noisy environment or due to constraints regarding infrastructure components, the used protocol is not always optimal for a specific situation which sometimes may lower the performance of the system.
Constraints regarding infrastructure components may e.g. occur when a new type of transceiver supporting a new IR protocol is introduced. A physical FL type may support both the new IR protocol and au older one. Which one to be used is determined by the transceiver type.
The object of the present invention is to achieve a system where an optimal performance of the system is achieved.